For users with the latest & greatest Macs, the animations Lion added are probably barely noticeable. But for those of us running it on older Macs, it’s painfully slow and quite annoying. Thankfully, much like removing the new Mail animation I wrote about last week, you can remove the animation completely.
Launch the Terminal app and type the following and hit Return after:
defaults write com.apple.dock expose-animation-duration -float 0
Before the change takes affect, you need to restart OS X’s Dock, which you do by typing the following in the Terminal and hitting Return:
killall Dock
Thanks to OSXDaily for the tip, and a few more adjustments you can make to Mission Control’s animation, including restoring it to its original state.